Presentation Details

Abstract Resume

Background:
Goalball is a paralympic disciplines designed for visually impaired athletes. The goal is that two opposing teams, each consisting of 3 players try to score points by rolling the ball into the
oppositions’ net. Players wear blindfolds to guarantee equal impairment. The ball contains bells allowing players to echolocate movements. So far only very few studies in the field of Goalball
performance analysis can be found. The purpose of this study is to analyze possible effects of rule changes made by IBSA-Subcommittee Goalball in 2014 (change of 10-Sec. Violation-Rule and
3-Time-Bowling Rule per player). This includes information’s about changes within general structure of performance. Furthermore influence of playing techniques on performance parameters are the focus
of this investigation.
Methods:
Altogether, performance in 145 Goalball matches (Paralympics 2012, European Championships 2013; World Championships 2014; 79 men games, 66 women games) was analyzed. A semi-automatic computerized
software was used to analyze each bowl (n = 24066) regarding scoring sector, ball speed and individual bowling patterns.
Results:
Neither men nor women show significant difference regarding to no. of bowls, between games in 2013 and 2014 (Men: U = 146.50; p = .143; r = -.22 Women: U = 119.00; p = 0.78; r = -.28). Concerning
penalties per game women games show no significant difference between 2013 and 2014 (U = 155.00; p = .479; r = -.11), instead of a significant change in men games in 2014 (F = 4.95; df 0 41; p = .006;
d = -.95). The remove of 3-Bowl-Violation must be analyzed for each individual player and team. Individual case examples show a tendency towards the exploitation of this rule change in its
dependencies of team characteristics (e.g. Finland). A statistically significant effect of scoring goals is proven by using so called “bouncing balls” in men, χ2 (1, N = 11501) = 3,77, p = ,02 and
women games (χ2 (1, N = 9093) = 29,57, p < ,001). The statistical examination by the χ2-test method shows no significant difference according to the bowling technique “Rotational” vs. “Regular” in men
games, χ2 (1, N = 11501) = 1,88, p = ,17. Contrary to this, the statistical evidence that the bowling technique “Rotational” is more effective in women games, χ2 (1, N = 9095) = 20,22, p < ,001.
Scoring sector analyses show significance differences on sector 3 and 7 (n = 19754; χ2 = 7.50, p ≤ .005).
Conclusions:
In this study, an investigation on effect of rule changes was conducted. The change in the rules was wisely executed so that the structure of the game was only minimally changed. Differences of
techniques for performance were demonstrated statistically. Scoring sector analysis proofed coaches and players opinion that it is easier to score on sectors, where defensive responsibilities of two
players overlaps. Additional research should further investigate underlying causes of observed bowling patterns.